Sorry guys, I think I'm wrong about the treadmill. I think it's the same. That means my equation modification is wrong. Which means air,...

The streamers fell almost exactly as the wind equation predicted. The bottom one fell at 13.3 and the other two at about 15. If the prop were an...

How was the wind measured during the trial? Based on the equations below for wind above a lake, the wind at the bottom of the propeller may have...

Yes, air velocity meters (or pressure meters) on both sides of prop, relative to side of cart or wheels (not relative to each other). If...

JB, I didn't know how to answer the question. Let me try. As my response shows, I do not consider the treadmill and wind cases to be...

Sail has much higher efficiency, according to Bauer. At slow speeds the blades are turning, so are they not acting like a true prop (at least a...

If I am correct in saying there is a difference between the treadmill and the wind, then the difference in acceleration is not easy to explain...

I can't think of a difference. Can the blackbird get 3.5x in less than 11.50 mph? My equation says no. I'm checking it for accuracy.

Yes, my answer was in post 390. Direction of energy/power flow depends on chosen frame of reference combined with chosen direction for the...

"it only has energy in relation to something that is moving at a different velocity" That's what I said. I want to view the ground as stationary...

I'm not confused about anything. Yes, a leverage viewpoint might be OK. I haven't thought or read about that perspective. When I do the math, I...

That's a good question because my answer seems to sum it all up best: If you consider yourself to be traveling forward, the wind. Backward,...

Case 1: A sail boat moving forward relative to the water at 2.5 mph with a 5 mph wind is taking energy from the air. Case 2: A sail boat...

Dr Drela and Dr Bauer predicted blackbird's max speed was 3.4x. My correction to the equation gave the measured 2.8x. I derived it from...

Can I get paid for this research? Your current set up should be able to get you up to 4x if you can get your L down to 0.25 in a 15 mph wind....

Now I see that I included a penalty of 20 pounds retarding force from the wheels that I shouldn't have. You should take a closer look at my...

How did you guys get 2.8 in 10 mph when Dr Bauer and Dr Drela's power analysis indicates only 18 pounds of thrust? I used the data below. Your...

You have not pointed out an error in my comments except to express your opinion. Do you have any writings on the subject I can critique for...

My first post has the easy intuitive explanation at the bottom. I am typing only for those who are serious about about getting the perfect prop...

Friction anywhere. They are both penalized by any friction, but to different degrees based on a difference in the pressure profile across the...